1. Field of the Invention
The present invention relates to an electrical system for an automotive vehicle. More specifically, the present invention relates to an automotive vehicle electrical system having a normal operation mode and a defog or deice operation mode. The defog operation mode is prevented from being activated until an engine idling gets stable even when the defog operation mode is selected, so as to improve the engine starting performance.
2. Description of the Background Art
There has been known an automotive vehicle electrical system having a normal operation mode and a defog or deice operation mode, such as described in Japanese Second Patent Publication No. 61-33735 and U.S. Pat. No. 4,780,619.
In such a known electrical system, however, when an engine starter switch is turned on to start the engine or restart the engine after the engine stall, with a defog mode selection switch being in ON state, a maximum field current is applied to a field winding of a generator to provide a higher output voltage of the generator required in the defog operation mode. Accordingly, a large back electromotive force is generated across stator windings of the generator, which is exerted onto the field winding in a manner to resist the rotation of same which is driven by the vehicle engine. Thus, the engine starting performance is impaired, resulting in the engine stall or in the unstable engine idling just after the engine is started.
Further, since the engine idle speed is controlled higher during the defog operation mode, i.e. while the defog mode selection switch is turned on, the engine idle speed rapidly increases just after the engine is started. This makes a driver feel uneasy about the operation of the engine.